Your CSS never leaves the browser
Compression runs locally in your tab using native JavaScript. No upload, no remote API, no analytics on the CSS content. Open dev tools network panel and watch zero outbound requests.
CSS Compressor in Your Browser
Paste CSS or drop a .css file. The result appears underneath as you type. Three compression levels, copy or save the minified output, everything runs locally in this tab.
Guide
How to compress your CSS
1
Add your CSS
Paste a stylesheet into the input area, or switch to "Upload .css file" and drop the file from your computer. Both modes feed into the same compressor.
2
Pick a compression level
Light keeps formatting and only removes comments. Standard strips whitespace, shortens hex colors, and trims redundant semicolons. Maximum also drops empty rules and license blocks.
3
See the result instantly
The minified output appears underneath as you type. The line above it shows the original size, the new size, and exactly how much you saved.
4
Copy or download
Use Copy to send the minified CSS to your clipboard, or Save .min.css to download it as a file. The filename matches whatever you uploaded.
What this CSS tool actually does
Every byte your stylesheet carries is a byte the browser has to download, parse, and apply before a first paint. Comments, indentation, and line breaks help you read code but mean nothing to the rendering engine. A minifier strips those bytes without touching the rules themselves, so the design renders identically and the file is roughly 20-40% smaller.
This compressor runs entirely inside your browser tab. There is no upload, no signup, no server log. Two input modes share the same engine: paste CSS straight from your editor, or drop a .css file from your computer (up to 5 MB). The result is shown the moment you finish typing.
Three presets cover almost every use case. Light keeps formatting and only removes comments. Standard does what most build tools ship: strips whitespace, shortens hex colors, trims trailing semicolons, removes units on zero values. Maximum goes further and also drops empty rules and license-style /*! comments.
Benefits
Why use this CSS compressor
Paste code or drop a file
Two input modes feed the same engine. Paste a snippet from your editor for quick tests, or drop a multi-megabyte .css file straight from your project folder.
Live compression as you type
No "compress" button to click. The minified output updates the moment you finish typing or pasting. Switch compression levels and the result re-renders instantly.
Savings in real time
The bar above the output shows original size, new size, and percentage saved. Typical real-world stylesheets drop 25-40% on the Standard preset.
Preserves licenses on request
Comments that start with /*! (the convention for license blocks used by jQuery, Bootstrap, and Normalize) survive Standard mode. Switch to Maximum if you want them removed too.
Copy or download .min.css
Send the output to your clipboard with one click, or save it as a .min.css file named after the source you uploaded. No watermarks, no daily limits, no signup.
FAQ
Frequently Asked Questions
Quick answers about CSS minification, what gets changed, and how privacy works here.
Is my CSS uploaded anywhere?
No. The CSS is compressed in your browser using native JavaScript. Nothing is sent to a server, nothing is stored, nothing is logged. Open dev tools network panel and you will see zero outbound requests during compression.
What is the difference between Light, Standard, and Maximum?
Light removes comments but keeps your formatting, useful when you still want to read the result. Standard does what most build tools do: strips whitespace, shortens hex colors, trims the last semicolon in each block, and removes units on zero values. Maximum adds two more passes that drop empty rules and remove license-style /*! comments.
Will compression change how my CSS renders?
No. Every transformation is lossless in terms of CSS semantics. Removing a comment, a newline, or a zero unit does not change a single declaration. If two stylesheets look identical in the browser before and after compression, both will paint the same pixels.
How much can I expect to save?
It depends on how your source is written. A heavily indented stylesheet with lots of comments often drops 35-45%. A file already run through a build tool like PostCSS or LightningCSS will only drop a few percent. The bar above the output shows the exact number for your input.
How big a file can I compress?
The upload mode accepts files up to 5 MB. The paste mode has no hard limit beyond what your browser comfortably handles, which is usually several megabytes. For files larger than that, a command-line tool will be faster and easier to script.
Why are my /*! license comments preserved?
The /*! prefix is a convention used by libraries (jQuery, Bootstrap, Normalize) to mark legally required attribution. By default the Standard preset keeps those blocks so your build stays license-clean. Pick Maximum if you want them removed too.
Does it work offline?
Once the page is loaded, yes. The compressor uses no remote libraries during operation. You can disconnect your Wi-Fi after the page loads and every feature still works, including drag-and-drop uploads and downloads.